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Selection of MOSFET for high current application.

Other Parts Discussed in Thread: CSD16570Q5B

I am looking for a MOSFET capable of handling a current range from 0 to 600A, where the input voltages range from 0.4 to 1.4 volts. Can you suggest a MOSFET with very low on resistance (Rds) or a parallel configuration to achieve the scenario. 

  • Hello Bhuvaneshwari,

    Thanks for your interest in TI FETs. The lowest Rds(on) FET in TI's portfolio is the CSD16570Q5B, 25V NFET in 5x6mm SON package. This package is capable of about 3W max power dissipation. I estimated you would need at least 10 FETs in parallel to conduct 600A. The estimated conduction loss per device is about 2.2W which is within the capability of the package. That's about 22W total dissipation in the FETs. I'm assuming VGS = 10V (gate drive) with a low side switch configuration (source grounded and load connected between input voltage and FET drain). If your gate drive voltage is 5V, then more parallel FETs (12 total) are required due to higher on resistance at VGS = 5V. Let me know if you have any questions.

    Best Regards,

    John Wallace

    TI FET Applications

  • Hello John,

    Thanks for reviewing my query. Could you please provide me the equation on how you have estimated the mosfet quantity for the parallel configuration. I appreciate your assistance and guidance on this matter.

    Best Regards,

    Bhuvaneshwari

  • Hello Bhuvaneshwari,

    I used an excel-based load switch tool available at the link below to calculate the conduction losses in the FETs. This tool does not allow for paralleling FETs but you can simply divide the current by the number of parallel FETs to estimate the losses. Attached is a prefilled spreadsheet assuming 10 FETs in parallel (60A/FET). I had to use 1.5V input voltage because that's the lowest value the tool accepts.

    https://www.ti.com/tool/LOAD-SWITCH-FET-LOSS-CALC

    LOAD-SWITCH-FET-LOSS-CALC_Rev2.xlsm

    Best Regards,

    John